102,027 research outputs found
Stochastic Simulations of Mixed-Lipid Compartments: From self-assembling vesicles to self-producing protocells
No full textThe computational platform ENVIRONMENT, developed to simulate stochastically reaction systems in varying compartmentalized conditions [Mavelli and Ruiz-Mirazo: Philos Trans R Soc Lond B Biol Sci 362:1789-1802, 2007; Physical Biology 7(3): 036002, 2010], is here applied to study the dynamic properties and stability of model protocells that start producing their own lipid molecules (e.g., phospholipids), which get inserted in previously self-assembled vesicles, made of precursor amphiphiles (e.g., fatty acids). Attention is mainly focused on the changes that this may provoke in the permeability of the compartment, as well as in its eventual osmotic robustness
Recenti progressi nello studio di oligoelementi di rilevanza per la patologia clinica mediante tecniche chimico-fisiche in particolare di risonanza magnetica
No full textThe polynomial approach to the LQ non-Gaussian regulator problem
No full textA new approach for the solution of the regulator problem for linear discrete-time dynamical systems with non-Gaussian disturbances is proposed. This approach generalizes a previous result concerning the definition of the quadratic optimal regulator. It consists in the definition of the polynomial optimal algorithm of order v for the solution of the linear quadratic non-Gaussian stochastic regulator problem for systems with partial state information. The validity of the separation principle has also been proved in this case. Numerical simulations show the high performance of the proposed method with respect to the classical linear regulation techniques
Optimal quadratic solution for the non-Gaussian finite-horizon regulator problem
No full textIn this paper, the problem of the optimal quadratic regulator for non-Gaussian discrete-time stochastic systems with a quadratic cost function is considered. The main result here obtained is that such optimal control can be derived from the classical LQG solution by substituting the linear filtering part with a quadratic optimal filter. Numerical results show high performance of this method. (C) 1999 Elsevier Science B.V. All rights reserved
Evidence for superoxide generation from the autoxidation of the favism-inducing aglycone divicine
No full textThe formation of the superoxide anion radical (O2-) during the autoxidation of divicine, an unstable aglycone involved in the hemolytic anemia occurring in favism, has been demonstrated by EPR with two different procedures. In the first case (chemical method) an O2--mediated reduction of a nitroxide by cysteine was shown to occur when divicine was allowed to cycle between the oxidized and the reduced form. In the second case (enzymatic method) the specific reaction between superoxide and superoxide dismutase was used as superoxide detector. It was shown that the enzyme attained a steady-state condition when mixed with divicine in the presence of air, as monitored by EPR evaluation of the oxidation state of the catalytic copper: this result is a direct, specific indicator of an O2- flux
A synthetic biology approach to bio-chem-ICT: first moves towards chemical communication between synthetic and natural cells (* Rampioni, Mavelli and Damiano have contributed equally to this work)
No full textIn this article we present novel aspects of the impact that synthetic biology (SB) can express in a field traditionally based on computer science: information and communication technologies (ICTs), an area that we will consider taking into account also possible implications for artificial intelligence (AI) research. In the first part of this article we will shortly introduce some recent theoretical and experimental issues related to our approach in SB, discussing their relevance and potentiality in the field. Next, we define an original SB research program that aims at contributing to the development of bio-chem-ICTs and AI based on chemical communication between natural and synthetic cells. In particular we present (i) a mathematical model that allows us to simulate the main features of the system under construction; and (ii) preliminary wet- lab experiments showing the feasibility of our research program. Based on the bottom-up construction of synthetic cells, the traits of this novel approach and their connections with recent conceptual and technological trends are finally discussed
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